The rapid technological advancement of electronic components has created a growing need to provide thermal management systems which provide higher capacities to cool the electronic components and/or which provide localized solutions to reduce heat flux and temperature gradients across the electronic component being thermally managed.
The localized and general increases in power for electronic components, combined with decreasing sizes and packages of the components, has created a need for improved thermal management. There is a need for higher heat transfer capabilities and for dissimilar heat transfer rates across an electronic component to reduce or eliminate the heat flux and/or temperature gradient across the electronic component being thermally managed.
In a typical evaporative spray cooling system for example, cooling is achieved by maintaining a thin liquid film flow over the device or electronic component to be cooled. If there is insufficient flow or coverage of the coolant, the liquid layer covering the electronic component will dry out and cause the component to overheat if it must rely on mere convection for the heat transfer. If excessive coolant flow to the component is provided, the device will become flooded and may tend to produce hot spots which may not be sufficiently cooled, which may lead to localized failure.
In a given electronic component there may be one or more hot spots where appreciably more heat must be removed to maintain a more uniform heat or temperature distribution across the component. Temperature gradients across electronic devices are generally not preferred. For most electronic devices, the localized failure on an electronic component results in the failure of the entire electronic component.
In order to achieve the desired thermal management and/or cooling, the vapor generated at the surface of the component is allowed to flow over the device, which generally requires an effective escape route or area to which the vapor and/or coolant must be allowed or directed to flow, thus maintaining the critical flow over the area of the electronic component being thermally managed.
In most embodiments of spray cooling systems, the flow of the vapor over the surface of the liquid coolant on the electronic component contributes to the maintenance of the flow of the coolant over the recipient surface, and to the effectiveness of the cooling. Providing for the continued flow and the escape or removal of the vapor generated at the surface of the electronic component further helps reduce the chances of film boiling heat transfer failure mode, also generally referred to as burnout.
Even when the volume flux of coolant is properly matched to the heat flux of the device, the excess fluid sprayed within a cavity should be managed to prevent the overflow from adjacent components from interfering and causing flooding type failure conditions. One way to manage the excess fluid is by the method and ways described in U.S. Pat. No. 5,220,804, which is incorporated herein by this reference. In these general types of embodiments, the momentum from the atomized droplets is utilized to contribute to the vapor flow over the surface within the chamber. The momentum from the atomized droplets may also be conserved by providing an escape route or slot which provides the channel, means or area to allow the flow, reducing the resistance to the flow or momentum of the atomized droplets. The conservation of the momentum reduces or avoids a counter-flow or back-flow of coolant and/or vapor against the flow of the atomized droplets to the recipient surface. Hence the combined utilization and conservation of the momentum of the atomized droplets in some embodiments or applications, contributes to the overall effectiveness of these systems.
It is an objective of some embodiments of this invention to provide a thermal management or evaporative spray cooling system to deliver higher capacity cooling to one or more electronic components.
It is an objective of some embodiments of this invention to provide a thermal management system which reduces the temperature gradient across an electronic component being cooled, by providing greater cooling capacity to local areas of an electronic components
It is an objective of some embodiments of this invention to provide a system for customizing a thermal management system to a recipient electronic component based on altering and localizing the approximate impingement angles of coolant droplets impacting the recipient surface, in a spray cooling environment.
It is an objective of some embodiments of this invention to provide a thermal management system which tends to equalize the travel distance of atomized coolant droplets leaving an atomizer at different radial angles, to a recipient surface.